The Analytic Core (AC) will provide expertise and systems for the conduct of qualitative studies, randomized controlled trials (RCT), and economic studies to support the aims of the iTech and its research and pilot studies, interactions within the ATN, and with NICHD. This work is organized across three aims that follow the research project lifecycle. Throughout the development (Aim 1), execution (Aim 2), analysis, and dissemination (Aim 3) phases of each study activity, the AC will responsibly and strategically manage its resources to foster a collaborative environment, maintain scientific rigor, and ensure timely work completion.It is composed of a Leadership Team, co-directed by Drs. Eli Rosenberg and Kathryn Muessig, and three subteams: the Randomized Controlled Trial (RCT), Cost Analysis, and Qualitative Teams. The first aim supports the development of iTech studies' qualitative, RCT, and costing activities by consulting on valid study design and establishing best-practice data collection systems and procedures. The Qualitative Team will work with research project PIs to develop valid and consistent (between-study) protocols, secure IRB approval, and design systems for qualitative data collection, storage, and analysis. The RCT Team will implement web-based recruitment screener and computer audio-assisted interview tools, design case report forms and collection system, develop and implement randomization plans and systems, and implement data capture and storage systems for study app usage, laboratory, and retention data. The Cost Analysis Team will work with project PIs to develop cost input parameters and collection tools. The second aim supports protocol implementation through the collection and maintenance of high-quality study data and real-time monitoring of study progress. For all research activities, the AC will provide data to the Management Core to monitor accrual on a weekly basis during active enrollment, to ensure each study is meeting enrollment targets within estimated timeframes. The RCT Team will routinely summarize study data to monitor all key domains of RCT activities, in the form of study progress reports, data quality reports, and research data reports. When recommended by NICHD for a given RCT protocol, the AC will act to assemble a DSMB. The third aim is to ensure that data analyses are conducted to the highest scientific standards and that results are dissemination in a timely way. In addition to supporting the iTech research and pilots studies, the AC will work collaboratively with the Management Core to ensure project and subject recruitment venue (SRV) milestones are met, data standards are upheld and dissemination is timely. Collaboration with the Technology Core will serve to ensure participant Recruitment and Retention and analysis of self-collected testing specimens. The AC will also serve as a resource to other funded U19s providing technical assistance on measurement and analysis of technology-based data systems.